Recent studies suggested that blue light may present a hazard to the retina of the ageing population. Yellow IOLs, which absorb blue-light, mimic the transmission characteristics of an aged human crystalline lens, protect lipofucsin-containing retinal pigment epithelial cells from being damaged by blue-light. There is indirect evidence that the blue light absorption IOL may reduce the risk for macular degeneration or its progression. On the other hand, the blue light blocking yellow lenses have been reportedly compromised the color perception, especially under scotopic (dim light) conditions, such as night driving. SmartYellowTM Lens, a photochromic hydrophobic acrylic IOL is designed to overcome the dilemma of a yellow IOL. Under scotopic conditions wherein the UV and blue light is very weak or non-exist, SmartYellowTM lens remains clear like a normal UV-blocking IOL while under photopic conditions, such as outdoor in a sunny day wherein both UV and the blue light is abundant, it turns into yellow color; It blocks both UV light and blue light, thus providing additional protection for retina. PI's group has conducted preliminary experiments indicating that incorporating photochromic dyes into hydrophobic IOLs is feasible and resulted IOLs are biocompatible in a 6 month rabbit study (by Dr. Nick Mamalis at University of Utah). In addition, PI has also completed an accelerated UV ageing study indicating that the photochromic Matrix IOL has a lifetime 23 years, exceeding ISO (11979-5) requirement of 20 years. This grant application, when approved will pave the way for human clinical trials in the US in later 2008. Annual cataract procedures in the US alone exceed 2.5 million. SmartYellowTM lens not only blocks UV light, it also blocks harmful blue light when exposed to UV. Thus, it provides cataract patients with additional protection for retina by reducing the risk of macular degeneration or its progression. [unreadable] [unreadable] [unreadable]